SALICYLIC ACID 191 the sodiLiiT-^ phericite by means of a bent tube fixed through the tubulus of t*10 retort» anc^ terminating just above the substance. The tem~pGrnt"uie °* ^1C 01^"^at-n 's gradually raised from 140° to 180__loo0? whilst fresh surfaces are exposed by occasionally stirrinc*- vv/itl* a glass rod inserted for a moment through the tubulus A-t the end of four hours the temperature is raised to 190 —200° foir zxtiother hour, and the process stopped. During the heatinc^- %\. considerable quantity of phenol distils, and solidifies in the iiecrlc of l-nc retort, whilst the contents become dark coloured. The rn^iss is shaken out into a basin without disturbing the phenol in the necl£> anc^ the residue dissolved by filling the retort two- thirds full of water. This is poured into the basin containing the otHcii" portion, which soon dissolves. The solution is acidi- fied wit In concentrated hydrochloric acid, which throws down impure sn.lic.:ylic acid in the form of a dark brown pre- cipitate. "When cold, the precipitate is filtered at the pump, and w;Exsl"i<:i<^ with a little cold water. A further quantity may foo ol:>t*lined by evaporating the filtrate to a small bulk. It is purified l->y dissolving in water, boiling with a little animal charcon.1 n.iicl filtering. The filtrate deposits the acid, on cooling, in colov.irle.ss needles. Yield about 6 grams. J. C0T~Ir>0 Na + CO, = C(!II,O.CO.ONa Sodium phenyl ourboniUi!. 2. CeI-I0O.CO.ONa I )isodiuin siilicylulc. Projf*£??*-/****?*- Colourless needles; in. p. 155—156''; soluble in ilcohoi n.incl hot water, rex)1 parts water dissolve 0*225 part at 15° ancl 7~<J^5 parts at 100". Iteu£'jft&?zs'. r. Dissolve a little of the acid in water and add a drop of" f<e rric chloride. A violet colouration is obtained. 2. Gi"in.cl v.ip some of the acid with soda-lime and cover with a shallow In.yor of the same substance. On heating strongly the smell of* pliciiiol is perceived. C0I-I.,<OH)CO.OH + CaO = C6HflOH + CaCO;J. See ^4.jp2&*??uiiX) p. 297.